One important aspect of interoperability between applications are open standards for file formats, network protocols and other ways of interaction or data exchange. This is important for interoperation of components inside of Kontact as well as in a wider context of interoperation with all kind of applications and servers from different provenience. The fact that the standards used are open is of particular importance for Free Software projects like Kontact to ensure that specifications and other information is available to all developers and the resulting code is free for distribution under Free Software licenses.
Kontact makes use of a wide variety of open standards. It implements many of the mail-related RFCs, including POP [18], IMAP [19] and SMTP [20]. The address book component uses vCard [21][22] as storage and exchanges format, and provides support for LDAP [23] as an access protocol. Calendaring is based on iCalendar [24] and the associated group scheduling standards iMIP [26] and iTIP [25].